National Committee on Marine Sciences (NCMS)
Permanent URI for this communityhttps://repository.unesco.gov.ph/handle/123456789/6
Browse
Search Results
- Utility of low-cost recreational-grade echosounders in imaging and characterizing bubbly coastal submarine groundwater dischargeGabuyo, Mary Rose P.; Siringan, Fernando P. (Elsevier, 2022-01)Despite the growing knowledge on the significance of submarine groundwater discharge (SGD), mapping its occurrence is a continuing challenge. This study explores the capability and applicability of low-cost, off-the-shelf, recreational-grade echosounders (RGESs) to image different types and locate point sources of bubbly coastal SGD. Standard and systematic methodologies for efficient imaging and processing were established. The use of RGES was validated using a research-grade side scan sonar (RGSSS), continuous resistivity profiling, conductivity-temperature-depth casting, and MantaCam and SCUBA diving surveys. Lower frequencies (77/83 kHz) of RGESs showed more distinct acoustic signatures of bubbly SGD, as these were nearly the same as the effective resonance frequency of the bubbles. The clusters of bubbly discharges have higher backscatter strength than the water column noise, resulting in the definitive and convenient manual detection of SGD features. Hence, showing more accurate point sources of SGD. Three types of known SGD occurrence were identified and characterized based on acoustic behavior and spatial distribution: 1) sparse, discrete and sporadic discharge over wide area, 2) curtain, high and continuous bubble concentrations from widespread discharge, and 3) spring, direct bubble discharge from intense seafloor degassing at a single point source. These results showed that RGES provides a good alternative for more efficient and cost-effective preliminary coastal SGD works. Additional research on areas with water-dominated discharge but no bubbling is recommended.
- Multifaceted assessment of wastewater-based epidemiology for SARS-CoV-2 in selected urban communities in Davao City, Philippines: A pilot studyOtero, Maria Catherine B.; Murao, Lyre Anni E.; Limen, Mary Antoinette G.; Caalim, Daniel Rev A.; Gaite, Paul Lorenzo A.; Bacus, Michael G.; Acaso, Joan T.; Miguel, Refeim M.; Corazo, Kahlil; Knot, Ineke E.; Sajonia, Homer; de los Reyes, Francis L.; Jaraula, Caroline Marie B.; Baja, Emmanuel S.; Del Mundo, Dann Marie N. (MDPI, 2022-07-19)Over 60 countries have integrated wastewater-based epidemiology (WBE) in their COVID-19 surveillance programs, focusing on wastewater treatment plants (WWTP). In this paper, we piloted the assessment of SARS-CoV-2 WBE as a complementary public health surveillance method in susceptible communities in a highly urbanized city without WWTP in the Philippines by exploring the extraction and detection methods, evaluating the contribution of physico-chemical–anthropogenic factors, and attempting whole-genome sequencing (WGS). Weekly wastewater samples were collected from sewer pipes or creeks in six communities with moderate-to-high risk of COVID-19 transmission, as categorized by the City Government of Davao from November to December 2020. Physico-chemical properties of the wastewater and anthropogenic conditions of the sites were noted. Samples were concentrated using a PEG-NaCl precipitation method and analyzed by RT-PCR to detect the SARS-CoV-2 N, RdRP, and E genes. A subset of nine samples were subjected to WGS using the Minion sequencing platform. SARS-CoV-2 RNA was detected in twenty-two samples (91.7%) regardless of the presence of new cases. Cycle threshold values correlated with RNA concentration and attack rate. The lack of a sewershed map in the sampled areas highlights the need to integrate this in the WBE planning. A combined analysis of wastewater physico-chemical parameters such as flow rate, surface water temperature, salinity, dissolved oxygen, and total dissolved solids provided insights on the ideal sampling location, time, and method for WBE, and their impact on RNA recovery. The contribution of fecal matter in the wastewater may also be assessed through the coliform count and in the context of anthropogenic conditions in the area. Finally, our attempt on WGS detected single-nucleotide polymorphisms (SNPs) in wastewater which included clinically reported and newly identified mutations in the Philippines. This exploratory report provides a contextualized framework for applying WBE surveillance in low-sanitation areas.The authors thank the Davao City Health Office, the local government units under the City Government of Davao, the partner hospitals for their support and assistance, and Diana Aga for discussions on sample collection and analyses. The authors would also like to thank the members of the Bortz Virology Laboratory at the University of Alaska Anchorage- Ralf Dagdag and Matthew Redlinger, Amanda Warr from the Roslin Institute, Nicole Wheeler from the University of Birmingham, Lara Urban, co-founder of PuntSeq, and Joe Russell from MRI Global for their expert advice in nanopore and wastewater sequencing.
- Clay mineral nanostructures regulate sequestration of organic carbon in typical fluvial sedimentsSong, Hongzhe; Liu, Zhifei; Lin, Baozhi; Zhao, Yulong; Siringan, Fernando P.; You, Chen-Feng (Elsevier, 2024-02-15)The association between clay minerals and organic carbon is pivotal for understanding transport, burial, and preservation processes of sedimentary organic carbon. However, fine-scale microscopic studies are still limited in assessing the effect of diverse clay mineral structures and properties on organic carbon sequestration. In this study, we employed X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and transmission electron microscopy coupled with energy dispersive spectroscopy and electron energy loss spectroscopy analyses to investigate the nanoscale interaction between clay minerals and organic carbon of two typical fluvial sediment samples with contrasting clay mineral compositions and organic carbon origins. Sample from Taiwan shows abundant illite and chlorite with petrogenic organic carbon, while sample from Luzon has significant smectite with pedogenic organic carbon. We observed that the nanostructure of the clay minerals controls the distribution of organic carbon. In the Luzon sample, the organic carbon is tightly associated with smectite, occupying expandable interlayer spaces. In the Taiwan sample, however, the organic carbon is primarily confined on the surface and edge of illite. These findings offer valuable insights into the selective association of organic carbon with clay minerals and underscore the role of clay mineral nanolayer structures in governing the occurrence and preservation of organic carbon in sediments. A comprehensive understanding of these interactions is crucial for accurate assessments of carbon cycling and sequestration in the natural environment.We sincerely thank Shunai Che and Lu Han for their help in TEM experiments and data processing. We thank Editor Dr. Andrew Hursthouse for handling the manuscript and two anonymous reviewers for their constructive comments on the early version of this paper. This work was supported by the National Natural Science Foundation of China (42130407, 42188102, 42306066) and the Interdisciplinary Project of Tongji University (ZD-22-202102).
- Emerging pharmaceutical contaminants in key aquatic environments of the PhilippinesMariano, Shyrill Mae F.; Angeles, Luisa F.; Aga, Diana S.; Villanoy, Cesar L.; Jaraula, Caroline Marie B. (Frontiers Media SA, 2023-09-13)Pharmaceuticals in natural waters are considered emerging pollutants due to their low concentrations and the negative effects they pose to the environment. Common sources of such pollutants include untreated wastewater from hospitals, residential, industrial, and agricultural sources. Many wastewater treatment methods only remove a subset of all pharmaceuticals from the wastewater; remaining pharmaceuticals are discharged into natural waters, and ultimately drain into coastal areas. Regions without proper wastewater treatment are especially susceptible to such contamination. This study deals with the distribution, sources, and seasonal variability of pharmaceuticals in key aquatic systems in the Philippines. Two watershed continuums (Davao Gulf, Davao City; Macajalar Bay, Cagayan de Oro City); two tourist areas (Boracay Island, Aklan; Mabini, Batangas); and one pristine atoll (Tubbataha Reefs, Palawan)—all with varied prevailing human population pressures—were studied. Samples of hospital wastewater as well as groundwater, surface and bottom water samples from rivers and coastal seas collected during dry and wet seasons were analyzed using solid-phase extraction and liquid chromatography-tandem mass spectrometry. Thirty-four target pharmaceutical residues and antibiotics were extracted and quantified. Acetaminophen was detected at concentrations of up to 289.17 ppb in freshwater samples, and at concentrations of up to 253.39 ppb in seawater samples. Ubiquitous to all the sites was caffeine, reaching 1848.57 ppb. Sulfamethazine, a commonly used veterinary antibiotic, was detected at 764.91 ppb in a river site in Cagayan de Oro. Untreated hospital wastewater contained metformin, iopamidol, sulfamethoxazole, acetylsulfamethoxazole, ciprofloxacin, and azithromycin, but these pharmaceuticals were not detected in other river and coastal waters. Samples collected during the dry season exhibited higher concentrations than those from the wet season, which appears to be related to increase in transient populations from tourism activities as well as dilution. The presence of pharmaceutical residues and antibiotics in these areas and the potential impact on the environment indicate the need for stricter wastewater management measures, particularly in communities located near water bodies. As the results of this study show, such measures might be most beneficial and effective if imposed during dry season and in areas open to tourism.We thank the crew and researchers aboard M/Y Panata expedition PA0421 to Tubbataha in October 2019 and cruise to Boracay December 2019. Our gratitude to Mary Antoinette Limen, Mishel Valery Rañada, Gio Ferson Bautista, and Ernest Guiller Pineda for helping us in the field, and to Lahiruni Halwatura for assisting in the creation of a standard calibration curve for saltwater.
- Feeding and reproductive phenotypic traits of the sea urchin Tripneustes gratilla in seagrass beds impacted by eutrophicationBangi, Helen Grace P.; Juinio-Meñez, Marie Antonette (MDPI AG, 2023-07-11)The sea urchin Tripneustes gratilla is a major grazer and is, hence, an excellent key model organism to study to gain a better understanding of responses to changes in its habitat. We investigated whether there are significant variations in the feeding and reproductive phenotypic traits of populations from three seagrass bed sites, with respect to their proximity to fish farms in Bolinao, northwestern Philippines. We established three stations in each of the three sites: the far, the intermediate, and those near the fish farms, and compared the sea urchins’ phenotypic traits and determined whether these were related to seagrass productivity and water parameters. Regardless of the sampling period, adult sea urchins (66.92 ± 0.27 mm test diameter, TD, n = 157) from the areas intermediate and near to the fish farms had significantly lower indices of Aristotle’s lantern, gut contents, gut and gonads, and lower gonad quality (high percentage of unusual black gonads), compared to those from the far stations. Multivariate analysis showed that the smaller feeding structures and gut, lower consumption rates and lower gonad indices and quality of sea urchins in the intermediate and near fish farms were positively related to lower shoot density, leaf production and species diversity, as well as lower water movement in those stations. The larger size of the Aristotle’s lantern in the far stations was not related to food limitations. More importantly, the phenotypic variability in the feeding structures and gonads of sea urchins in the same seagrass bed provides new evidence regarding the sensitivity of this species to environmental factors that may affect variability in food quality.The authors are very grateful to the anonymous reviewers for providing significant comments and suggestions to improve the manuscript. They are also indebted to the following: Rene R. Rollon, for providing advice on seagrass sampling techniques; Symon Dworjanyn, for providing valuable inputs in the earlier version of this manuscript; Marilou San Diego-McGlone, for providing some water quality data in Bolinao; Charissa M. Ferrerra, for the assistance provided on the Ocean Data View mapping software; Ma Josefa R. Pante, for some statistical advice. The authors would like to thank Jay R Gorospe for reviewing and providing valuable suggestions on the revised version of the manuscript, likewise to Lambert Meñez, for critically editing the manuscript, and to Jerwin Baure for additional assistance in copy editing the manuscript. The authors are thankful to Larry Milan, Jack Rengel, Lawrence Ramoran, for assisting the authors in field sampling and laboratory processing of samples. L. Milan, Jan Noelle Rimando and Aphrodite Entoma assisted in laboratory analysis of samples, particularly in gut content analysis.